Energy Independence (Part Two): Is Ethanol the Answer?

In 2007, the US consumed 3.4 billon barrels of gasoline. That’s 143 billion gallons. For the U.S. to ever become energy independent, we have to figure out where we are going to get all of that gas? Could ethanol be the answer? Here is the Good and the Not-So-Good on ethanol.


First, let’s be clear on a few things. Ethanol is simply alcohol, ethyl alcohol to be exact. It has other names, like grain alcohol, but it’s the kind of alcohol you drink. It’s not the stuff in your medicine cabinet, I hope.

It’s interesting to note that Henry Ford first designed the Model T to run on ethanol. He thought the ability for most people to make their own fuel instead of having to rely on industry was a good one. If it wasn’t for Prohibition, ethanol may have emerged as the predominant fuel in the 20th century and most of us would have never heard of places like Iran, Iraq and Saudi Arabia.

Most cars will run just fine on ethanol blended with regular gasoline, without any modifications. In fact, the gas that you bought this morning was likely already 10% ethanol or E10. Many states have mandatory ethanol laws. The actual blend percentage is changed according to the season for some climates. Some claim that most cars on the road today could burn a much higher ethanol blend, 20%-50%, without harm.

Car makers now offer “flex fuel” vehicles (in some limited markets). A flex fuel vehicle (FFV) is designed to run on any ethanol blend up to 85%, E85. There is a push to mandate “flex fuel” cars for all new cars sold in the US. The estimated cost to the automaker is minimal, about $5. (Reference needed.) Existing cars can be converted to use E85 (or even 100% ethanol) fairly easily and cheaply.

100% ethanol has an octane rating of 116, but higher octane doesn’t mean more power. The higher octane number means the fuel can be used in higher compression engines. If you were to use a low octane fuel, in a high compression engine, it would “knock.” If your owners manual says to use premium (92 octane) fuel, then you should buy premium. Likewise, if the car was designed to use regular gas, you will not get any benefit from using the higher grade. (By the way, E85 is 105 octane, regular gas is 87 octane.)


The disappointing fact is that ethanol contains about 25% less energy than gasoline. Therefore, users of E85 should expect about 25% less gas mileage than users of E10. So, if you would normally drive 400 miles on a tank of regular, you should expect to run out at around 300 miles with E85. Now if E85 was $3/gal and E10 was $4/gal, then it’s a break even situation. The cost per mile would be the same. In some areas of the country, the price difference is great enough that E85 is the most economical choice. On average though, the price spread is not great enough. (National average E85: $3.31, Gas: $4.01, July 26 2008) If you are lucky enough to own a FFV or a conversion, you’ll have to do a little bit of mental math at the pump. Multiply the E85 price by 1.33 to get the equivalent gasoline price.

Last week, a truck stop in Eagan, Minnesota had E85 for $2.51 and regular gas for $3.99. Since $2.51 x 1.33 = $3.34, the E85 was a better choice by 65 cents a gallon.

Ethanol can be made from a variety of feed stocks. In the US, corn is the major player but this is likely to change, given the high corn prices and advances in alternative ethanol production techniques. Let’s talk corn.

Last year, the US produced 37% of the world’s corn supply. According to the USDA, we planted over 70 million acres and harvested over 10.5 billion bushels of corn. That’s about 150 bushels per acre, a bit low compared to the 300-500 bushels average yield per acre that I have seen in quoted in many articles. Perhaps it was just an off year.

The U.S. currently has the capacity to produce nearly 3.7 billion gallons of ethanol annually at 85 ethanol plants. I have seen claims that these plants are able to produce anywhere from 2.5 to 2.9 gallons of ethanol per bushel of corn.

So, if corn-based ethanol is the sole answer, how much would we need to replace the 143 billion gallons of gasoline that we consumed last year with an equivalent amount of E85? Since E85 has a lower MPG, we would need 143 x 1.33 = 190 billion gallons of E85 to drive as far as we did on the gasoline. Since E85 is only 85% ethanol, we would need 190 * 85% = 162 billion gallons of ethanol to make it. This would save us about 80%, or about 115 billion gallons of gasoline. That’s got to hurt OPEC, right?

Ok, let’s head down to the feed store and get enough corn to make 162 billion gallons of ethanol. At the average yield of 2.7 gals per bushel, we will need about 60 billion bushels. Oops! That’s almost 6 times the total U.S. corn production last year. We will need to plant more…about 330 million acres more, and that’s if we intend to use 100% of it for ethanol production. If we still want to eat some of it, add another 60-70 million acres for a total of 470 million acres. That is roughly 25% of the land mass of the lower 48 states. That’s a whole lot of corn.

As you can see, corn-based ethanol alone cannot solve our problem. But it can be a contributor. Other methods of ethanol production such as from sugar cane or barley could make more efficient land use with less competition with food crops. Cellulose based ethanol promises to be even better, using any type of plant material like fast growing grasses or bamboo.

Just because ethanol is not the end-all cure-all doesn’t mean we should abandon it. We need to whittle away at that 143 billion gallons any way we can. Starting with conservation, i.e. driving less, using more efficient cars, and burning a combination of alternate fuels, we can make a huge difference. To that end, our government should require that all new cars sold in the US be flex fuel capable so that everyone can take advantage of the new fuel blends as they come to market.


About John Cox

I'm a 47 year old software engineer and father of four.
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